The present invention relates in general to closure assemblies including a threaded flange and a threaded closing plug wherein the flange is securely installed into a container end panel or drum head, as it may be called. The connection between the container end panel and the flange is designed to be secure and tightly sealed at that interface so as to prevent the flange from pushing in or out axially and to prevent the flange from rotating relative to the container end panel as the closing plug is tightened into position.
The flange is internally threaded for receipt of the externally threaded plug. As will be disclosed herein, these flange and plug closure assemblies typically include some type of sealing gasket or sealant, or both. As will be described, in the context of the present invention the referenced closure assembly includes, in addition to the flange and plug, an annular gasket that is positioned between the plug and a portion of the container end panel. Once the plug is properly tightened in position into the flange and the annular gasket is compressed radially, a leak-free closure assembly is created. In the present invention, all of the securement of the flange and sealing of the closure assembly is the result of the specific design, the ability to utilize higher crimping pressures and forces, and the positioning of the annular gasket for its radial compression between the plug and the container end panel. The inner surface of the plug, radially inwardly of its peripheral serrations, is angled to improve the interaction of the gasket with the plug and container end. Included as a part of this specific design refinement is an angled or contoured surface on the plug that receives the gasket. Gasket performance is enhanced by these design improvements as will be described.
More specifically, the present invention relates to the design and construction of a threaded flange and threaded plug combination wherein the dimensions and dimensional relationships are selected to create a smaller overall combination that can be used on smaller containers and provides the well established thread systems for dispensing and threaded drum accessories presently used. A structural feature related to this smaller size design is the forming of the container end panel as a back up to reinforce the wall of the flange during securement into the container end panel. A related design improvement includes various shaping and geometry refinements for the flange and for the plug that are intended to improve performance and provide additional benefits.
While threaded flange and closing plug combinations are known in the art, it is also known that significant differences in reliability and performance can result from relatively minor design changes. This is why it is important to understand the precise nature and importance of the specific dimensions, the dimensional relationships, and the shapes of the flange and the cooperating closing plug as part of the present invention. The specific features of the present invention and their importance to the overall reliability and performance of the disclosed closure assembly will be described herein.